摘要:

AbstractPeptide maps of recombinant human parathyroid hormone (rhPTH) were determined by both trypsin and V‐8 protease digestion with subsequent fast‐atom bombardment mass spectrometry (FAB‐MS). Coverage of the sequence was 85% when using trypsin and 90% when using V‐8 protease. Five rhPTH variants that were recombinantly produced as models of Asn deamidated type degradation products were measured, and molecular weight differences between their respective deamidated peptide fragments were completely detected. In the V‐8 protease digests of some variants, characteristic peptide ions caused by the deamidation were observed and this greatly facilitated the assignment and recognition of the deamidated position. Our data suggest that FAB‐mapping of rhPTH via the protease digestion methods used, appears to have great potential for structural investigations of

ISSN:0951-4198    

DOI:10.1002/rcm.1290090402

出版商:Heyden&Son Limited    

年代:1995

数据来源: WILEY

摘要:

AbstractA liquid chromatography/mass spectrometry methodology is described that enables the simultaneous estimation of the individual protein‐binding affinities of a mixture of compounds. This approach has proved to be robust and enables a series of molecules to be ranked according to their protein‐binding affinities within 20 minu

ISSN:0951-4198    

DOI:10.1002/rcm.1290090403

出版商:Heyden&Son Limited    

年代:1995

数据来源: WILEY

摘要:

AbstractFive synthetic opioid peptides that were designed to have specific opioid receptor‐binding properties were studied by low energy collision‐induced dissociation (CID) tandem mass spectrometry (MS/MS). The MS/MS data are required for the analysis of those peptides in ovine plasma in a study to determine the placental transfer of the peptide to the fetus. The synthetic enkephalin‐related peptides were: Tyr‐D‐Arg‐Phe‐Lys‐NH2, (DALDA), N,N‐diallyl‐Tyr‐Aib‐Aib‐Phe‐Leu‐OH, (ICI 174,864), Tyr‐D‐Thr‐Gly‐Phe‐Leu‐Thr, (DTLET),. Liquid secondary ion mass spectrometry (LSIMS) was used for sample desorption‐ionization, and a hybrid (E1BE2qQ) tandem mass spectrometer was used to collect the product‐ion spectra. A protonated molecule ion, [M + H]+, was observed for each peptide. Amino acid sequence‐determining fragment ions were produced by CID and collected by MS/MS for the three linear peptides, and also for the two disulfide‐bond‐containing peptides in their unreduced and dithiothreitol (DTT)‐reduced forms. The detection level for the [M + H]+ion of DTLET wasca. 3 pmol; and the stabiliti

ISSN:0951-4198    

DOI:10.1002/rcm.1290090404

出版商:Heyden&Son Limited    

年代:1995

数据来源: WILEY

摘要:

AbstractThe mass spectra of 1,3‐dithiole‐2‐thione‐ and tetrathiafulvalene‐fused thiophenes have been studied. Isomer differentiation was achieved by electron impact, metastable ion and collision‐induced dissociat

ISSN:0951-4198    

DOI:10.1002/rcm.1290090405

出版商:Heyden&Son Limited    

年代:1995

数据来源: WILEY

摘要:

AbstractThe electron impact mass spectra of some benzo[b]thiophene‐ and thieno[2,3‐b]thiophene‐2,5‐dicarbonyldichlorides, 2,5‐dicarbonyldianalides, 9‐anilido‐benzo[b]thienyl[2,3‐c]quinolones and 9‐anilido‐thieno[4,5‐b′]thienyl[2,3‐c]quinolones are discussed. Dominant peaks in dianilides are formed by cleavage of the CN bond on one side of the anilido group, as well as on the anilido group itself in anilidoquinolones. These ions fragment further by the cleavage of a CC bond in dianilides and the CONRPh group is lost directly, while the quinolonic part of the molecule in quinolones fragments with low probability. Characteristic fragment ions of dicarbonyldichlorides arise by

ISSN:0951-4198    

DOI:10.1002/rcm.1290090406

出版商:Heyden&Son Limited    

年代:1995

数据来源: WILEY

摘要:

AbstractA fused‐silica capillary high‐performance liquid chromatography column (i.d. 0.25 mm) packed with octadecylsilane‐bonded silica has been used on‐line with continuous‐flow negative‐ion fast‐atom bombardment (FAB) mass spectrometry for the separation and structural analysis of series of fatty acids and arachidonic acid metabolites derivatized with 4‐aminobenzenesulphonic acid. Negative‐ion FAB spectra of the derivatized lipids showed strong [MH]−pseudomolecular ions. Collision‐induced dissociation of these anions produced structurally informative daughter ions, arising from charg

ISSN:0951-4198    

DOI:10.1002/rcm.1290090407

出版商:Heyden&Son Limited    

年代:1995

数据来源: WILEY

摘要:

AbstractBiphenyl derivatives undergo extensive intraannular substituent migrations and subsequent intramolecularipsosubstitutions giving rise to a fluorenyi cation and a biphenylene radical cation as common products in mass spectrometry. For biphenyls bearing an alkyl group, interannular substituent migration resulting in a substituted tropylium ion is also observed. Electron‐withdrawing groups are found to be much more favourable to these reactions than the electron‐donating o

ISSN:0951-4198    

DOI:10.1002/rcm.1290090408

出版商:Heyden&Son Limited    

年代:1995

数据来源: WILEY

摘要:

AbstractExtracts of the red seaweedPorphyra umbilicalisare a valuable constituent of herbal medicines. The nucleotide complement of such an extract was purified and compounds identified by chromatographic behaviour, UV absorbance/pH profile, base‐to‐phosphate ratio, acid hydrolysis, and by fast‐atom bombardment mass spectrometry with mass‐analysed ion kinetic energy spectrum scanning. In addition to eighteen common nucleotides, and two cyclic nucleotides, fifteen novel nucleotides were identified, comprising eight deoxynucleotides and two cyclic deoxynucleotides, ten aminoacylnucleotides and two nucleoside trisphosphates together with 2′‐phosphoadenosine‐3′,5′‐cyclic pyrophosphate, 5′‐phosphoadenosine‐2′,3′‐cyclic monophosphate andN6,N6‐dimethyladenosine‐5′‐monophosphate. The possible origin and potential action

ISSN:0951-4198    

DOI:10.1002/rcm.1290090409

出版商:Heyden&Son Limited    

年代:1995

数据来源: WILEY

摘要:

AbstractThe stoichiometry of a noncovalent, hydrogen‐bonded supramolecular complex, hub(M)3·RCA3, was characterized using electrospray ionization from chloroform. The intact (1:3) complex was observed in the negative‐ion mode as a Cl−‐bound species using Ph4PCl as the source of the charge donor. Collisionally and thermally induced dissociation of the (1:3) complex resulted in the simultaneous loss of all the three RCA units, indicating a cooperative binding of RCA units in the (1:3) complex. These results suggest that the attachment of small, organic‐soluble ions may be a useful technique for mass spectrometric characterization of neutral supramolecular complexes that are stable or soluble only in non‐polar orga

ISSN:0951-4198    

DOI:10.1002/rcm.1290090410

出版商:Heyden&Son Limited    

年代:1995

数据来源: WILEY

摘要:

AbstractThe narrow‐band cooling of ion motion in the trap of a Fourier transform ion cyclotron resonance mass spectrometer (FTICR) using an external parallel resonant circuit is considered. The parameters of the circuit necessary for effective cooling of both axial and cyclotron ion motion are estimated. It is shown that the use of a resonant circuit may be helpful in studying the highly charged heavy ions produced in experiments with electrospray ionization combined with FTIC

ISSN:0951-4198    

DOI:10.1002/rcm.1290090411

出版商:Heyden&Son Limited    

年代:1995

数据来源: WILEY